EP3457064B1 - Dental oven and method for operating same - Google Patents

Dental oven and method for operating same Download PDF

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Publication number
EP3457064B1
EP3457064B1 EP17191620.8A EP17191620A EP3457064B1 EP 3457064 B1 EP3457064 B1 EP 3457064B1 EP 17191620 A EP17191620 A EP 17191620A EP 3457064 B1 EP3457064 B1 EP 3457064B1
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EP
European Patent Office
Prior art keywords
dental furnace
firing chamber
inlet
furnace according
connector
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EP17191620.8A
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German (de)
French (fr)
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EP3457064A1 (en
Inventor
Rudolf Jussel
Manuel Schlegel
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Ivoclar Vivadent AG
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Ivoclar Vivadent AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Ivoclar Vivadent AG filed Critical Ivoclar Vivadent AG
Priority to EP17191620.8A priority Critical patent/EP3457064B1/en
Priority to CN201811053346.2A priority patent/CN109512534A/en
Priority to US16/128,672 priority patent/US10955192B2/en
Priority to JP2018173578A priority patent/JP6814183B2/en
Publication of EP3457064A1 publication Critical patent/EP3457064A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B17/00—Furnaces of a kind not covered by any preceding group
    • F27B17/02—Furnaces of a kind not covered by any preceding group specially designed for laboratory use
    • F27B17/025—Furnaces of a kind not covered by any preceding group specially designed for laboratory use for dental workpieces
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C13/00—Dental prostheses; Making same
    • A61C13/20—Methods or devices for soldering, casting, moulding or melting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • F27D2021/0007—Monitoring the pressure

Definitions

  • the invention relates to a dental furnace according to the preamble of claim 1 and a method for operating a dental furnace according to the preamble of claim 13.
  • the invention is based on the object of creating a dental furnace according to the preamble of claim 1 and a corresponding method for operating the dental furnace according to the preamble of claim 13, which enable an optimized adaptation of the pressure situations and negative pressure situations to the requirements during the heat treatment process at low cost.
  • a single vacuum pump can be used to provide ventilation and deaeration measures that are optimally adapted to the requirements of the heat treatment process.
  • a T-shaped or Y-shaped connector is provided on the outlet connection of the dental furnace.
  • An inlet of the connector is connected to the outlet connection of the dental furnace.
  • the outlet of the connector is connected to the vacuum source, for example a corresponding suction pump.
  • a vacuum storage container can also be used instead of the suction pump.
  • the other inlet connection of the connector is connected to the ambient air, preferably in a controlled manner, i.e. provided with a flow resistance.
  • the flow resistance can be designed as a valve that is opened and closed depending on the requirements of the heat treatment process.
  • the dental furnace also has an inlet connection for the combustion chamber, which is preferably arranged opposite its outlet connection.
  • the inlet connection is also connected to a line, which is referred to as a second air line.
  • This has a flow resistance such as a filter and/or a valve.
  • the preferred procedure during the heat treatment process includes, as a first step, evacuating the combustion chamber in preparation for the heat treatment process.
  • the valves in the first air line and the second air line are closed and the suction pump works against the negative pressure until a predetermined negative pressure or the final vacuum is reached.
  • the heat treatment process is initiated by heating up the combustion chamber. Once a predetermined temperature level has been reached, the valve at the inlet connection of the combustion chamber is opened while the suction pump is running. The opening can be brief, for example for one second.
  • the fresh air introduced into the combustion chamber means that oxygen is supplied to the dental restoration without causing it to cool down significantly.
  • the cooling process can also be carried out by opening the inlet connection valve intermittently or by opening it completely. This allows the suction pump to draw the maximum volume flow through the combustion chamber.
  • the escaping air can be cooled, for example via a heat exchanger.
  • the cooling time can be greatly reduced if necessary by removing heat energy from the combustion chamber during the cooling process by flushing the combustion chamber with fresh air. If the inlet connection and outlet connection are arranged opposite one another, the heat is removed exactly where it is relevant for cooling, namely in the combustion chamber.
  • a heat exchanger can be provided which transfers heat from the suction line between the outlet of the connector and the vacuum source to the second air line at the inlet connection of the combustion chamber.
  • Such heat recovery is particularly beneficial during heating or during a period in the heat treatment process when the temperature is essentially to be maintained.
  • the combustion chamber can then be ventilated with warm fresh air without causing a sudden cooling and the associated risks in the heat treatment process.
  • the outlet connection of the furnace is at the top and the inlet connection at the bottom. If necessary, this allows the cooling of the combustion chamber to be optimized.
  • the connecting piece is made of a metal with good heat conductivity and a relatively large surface area. This makes it It is possible to dissipate heat at this point, after the connector is surrounded by ambient air.
  • the connector is preferably designed in such a way that gases with temperatures of up to 1200, 1400 or even 1600 degrees Celsius do not damage the metal connector at a given flow rate of several liters per minute.
  • the cooling through the heat exchanger at the connector cools the escaping air significantly, so that on the outlet side, for example, the maximum temperature is only 500 degrees.
  • valves in the first air line and the second air line can be designed as on/off valves. These are preferably closed when de-energized. However, if required, it is also possible to design the valve in the first air line and/or the valve in the second air line as an adjustable valve.
  • valve in the first air line which can also be referred to as a bypass valve, is partially opened, a flow restriction is created in the first air line. This allows the volume flow through the combustion chamber to be set to any value as required, so that part of the air discharged through the suction line is fed through the first air line and another part is fed through the second air line and the combustion chamber.
  • the first air line is designed in such a way that the fresh air supplied there cools other components.
  • suction pump is located immediately adjacent to the furnace and the suction line is therefore short, it may be advantageous to insert a cold trap into the suction line shortly before the suction pump.
  • the connector is attached directly to the dental furnace, for example, mounted on the furnace hood.
  • the connector may be useful to mount the connector a little away from the dental furnace, although it goes without saying that the short high-temperature line between the connector and the dental furnace must then be particularly temperature-resistant.
  • the inlet connection is then clearly adjacent to each of the connection pieces; the inlet connection and the connection pieces can then be arranged in a triangle, so that the fresh air entering through the inlet connection flows through the combustion chamber towards the connection pieces.
  • the suction pump can also be operated in a cyclical manner, so that a reduced volume flow is provided overall.
  • a comparatively long suction line creates a vacuum buffer that reduces the switching effects of the cyclical operation.
  • suction pump Since inexpensive suction pumps are typically quite loud, it is also possible to operate the suction pump outside the room in which the dental furnace is located.
  • the suction line can then be 5, 10 or even 20 meters long, so that a cooling trap is also unnecessary due to such a long suction line.
  • the maximum negative pressure or a lower negative pressure at different temperature levels, depending on the specifications of the heat treatment process.
  • the heat extraction can be minimized by the heat exchanger.
  • rapid cooling can also be achieved, whereby it is also possible to place a bypass over the heat exchanger on the inlet side so that its effect can be switched off if necessary.
  • the flow cross-sections of the lines can be adapted to the requirements in terms of flow technology. For example, if a suction line and a first and a second air line are used, the flow cross-section of the suction line is preferably twice as large as that of the air lines.
  • the connector which in the simplest version has two holes as inlets and one hole as outlet that meet each other.
  • the connector can therefore be Y-shaped, T-shaped or star-shaped. If necessary, it can also be provided with contact protection, for example a cover that leaves several centimeters of air.
  • the connector can also be provided with a relatively long connection piece for the first air line. This can also form cooling fins so that the entire metallic connector is cooled by the supply of cool air via the first air line.
  • the heat treatment process can be a sintering process or a firing process.
  • the dental furnace 10 shown schematically in the figure has a combustion chamber or a combustion space 12 which is formed in a furnace head 14.
  • the furnace head 14 closes at a parting plane 16 opposite a furnace base 18.
  • the furnace head 14 has heating elements which extend in a ring shape around the essentially cylindrical combustion chamber 12. Both the furnace head 14 and the furnace base 18 are provided with thermal insulation material 20, which can be designed as fireclay, for example, and is open-pored so that air can flow through it.
  • thermal insulation material 20 can be designed as fireclay, for example, and is open-pored so that air can flow through it.
  • the dental furnace 10 is provided with an inlet connection 22 for the supply of ambient air, which can also be referred to as fresh air, and with an outlet connection 24 to which a connection piece 26 is attached.
  • the connecting piece 26 is flanged directly to the housing wall 30 of the furnace head 14. It has an inlet 32 which is in flow connection with the open-pore thermal insulation material 20. It also has a second inlet 34 which is in connection with ambient air via a first air line 36.
  • the connecting piece 26 has an outlet 40 which is in flow connection with a suction line 42.
  • both the first air line 36 and the suction line 42 extend initially in the region of the furnace head 14 and from there downwards, i.e. into the region of the furnace base 18, and possibly laterally away from it.
  • the suction line 42 extends to a vacuum source 44, which is preferably designed as a suction pump 44 and whose exhaust air is preferably guided outside the room in which the dental furnace is located.
  • the inlet connection 22 is connected to a second air line 46.
  • the first air line 36 is provided with a bypass valve 48, via which it is connected to the ambient air via a filter and/or silencer 50.
  • the second air line 46 is provided with a second valve 54, via which it is connected to the ambient air via a second filter and/or silencer 56.
  • a vacuum sensor 60 is provided, which is connected to the interior of the dental furnace 10 via a branch line 62. This allows the existing vacuum in the combustion chamber 12 to be detected and used to control the two valves 48 and 54 and the suction pump 44.
  • bypass valve 48 and the second valve 54 are first closed and the suction pump 44 is switched on.
  • the second valve 54 can initially be held in the open position for a short time in order to safely remove any residual gases from the last heat treatment process.
  • the heat treatment process is then started by switching on the heating (not shown) for the combustion chamber 12. This is done under negative pressure, and the negative pressure is maintained after the suction pump 44 is operated during this time, so that even small leaks do not reduce the negative pressure.
  • the suction pump 44 is switched on again and the valve 54 is opened. This flushes the combustion chamber 12 with fresh air and, if necessary, it is possible to provide rapid cooling.
  • the suction pump 44 can also be switched on intermittently if the cooling is not to take place so quickly.
  • this method is more advantageous than opening the combustion chamber at the dividing line 16, since otherwise cooling air is always supplied suddenly.
  • bypass valve 44 is also at least partially opened during operation of the suction pump 44. This makes it possible to control the level of the negative pressure measured by the negative pressure sensor 60.
  • suction line 44 and the second air line 46 are brought close to one another and a heat exchanger is provided between them. This allows the hot oven air exiting from the outlet 44 to be thermally recovered and fed to the air line 46, which is particularly advantageous for heating.
  • the heat exchanger can also be provided with an additional bypass line on the inlet and/or outlet side, which in turn can have a valve.
  • the valve short-circuits the relevant side of the heat exchanger, so that the heat exchanger effect is bypassed, which is particularly beneficial for cooling and the supply of cold fresh air.
  • the dental furnace according to the invention can also be designed as a debinding furnace.
  • the exhaust air generated there can be removed particularly well according to the invention using the suction pump 44 according to the invention and the associated valves.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Clinical Laboratory Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Dentistry (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)

Description

Die Erfindung betrifft einen Dentalofen gemäß dem Oberbegriff von Anspruch 1 sowie ein Verfahren zum Betrieb eines Dentalofens, gemäß dem Oberbegriff von Anspruch 13.The invention relates to a dental furnace according to the preamble of claim 1 and a method for operating a dental furnace according to the preamble of claim 13.

Dentalöfen, bei denen über eine Unterdruckquelle der Brennraum unter Unterdruck gesetzt werden kann, sind seit langem bekannt.Dental furnaces in which the combustion chamber can be placed under negative pressure via a negative pressure source have been known for a long time.

Ein Beispiel hierfür ist der aus der DE 1 160 777 A1 bekannte Dentalofen. Bei dieser Lösung lässt sich der Brennraum unter Unterdruck setzen, aber auch über die gleiche Vakuumpumpe eine Hubeinrichtung betätigen.An example of this is the EN 1 160 777 A1 well-known dental furnace. With this solution, the combustion chamber can be placed under negative pressure, but a lifting device can also be operated using the same vacuum pump.

Derartige Lösungen sind in der Folge durchaus weiterverfolgt worden, wie es beispielweise aus der DE 102 08 801 C1 oder der DE 11 60 777B1 ersichtlich ist.Such solutions have subsequently been pursued further, as can be seen, for example, from the DE 102 08 801 C1 or the EN 11 60 777B1 is evident.

In der DE 43 03 458 C1 wird ebenfalls ein Dentalofen beschreiben.In the DE 43 03 458 C1 will also describe a dental oven.

Um den unterschiedlichen Anforderungen hinsichtlich der Steuerung des Unterdrucks gerecht zu werden, ist es auch bereits vorgeschlagen worden, mit regelbaren Unterdruckpumpen zu arbeiten. Diese sind jedoch vergleichsweise teuer, und bedienen auch eine entsprechend aufwendige Steuerung, beispielsweise mittels einer PID-Regelung. Demgegenüber liegt der Erfindung die Aufgabe zugrunde, einen Dentalofen gemäß dem Oberbegriff von Anspruch 1 sowie ein entsprechendes Verfahren zum Betrieb des Dentalofens gemäß dem Oberbegriff von Anspruch 13 zu schaffen, die preisgünstig eine optimierte Anpassung der Drucksituationen und Unterdrucksituationen an die Erfordernisse während des Wärmebehandlungsprozesses zu ermöglichen.In order to meet the different requirements with regard to the control of the negative pressure, it has already been proposed to work with adjustable negative pressure pumps. However, these are comparatively expensive and also operate a correspondingly complex control system, for example by means of a PID control. In contrast, the invention is based on the object of creating a dental furnace according to the preamble of claim 1 and a corresponding method for operating the dental furnace according to the preamble of claim 13, which enable an optimized adaptation of the pressure situations and negative pressure situations to the requirements during the heat treatment process at low cost.

Diese Aussage wird erfindungsgemäß durch die Ansprüche 1 bzw. 13 gelöst. Vorteilhafte Weiterbildungen ergeben sich aus den Unteransprüchen.This statement is solved according to the invention by claims 1 and 13 respectively. Advantageous further developments emerge from the subclaims.

Erfindungsgemäß ist es besonders günstig, dass mit einer Einfach-Unterdruckpumpe eine an die Erfordernisse des Wärmebehandlungsprozesses optimal angepasste Be- und Entlüftungsmaßnahmen getroffen werden können. Es ist an dem Auslassanschluss des Dentalofens ein T-förmiges oder Y-förmiges Anschlussstück vorgesehen. Ein Eingang des Anschlussstückes ist mit dem Auslassanschluss des Dentalofens verbunden. Der Ausgang des Anschlussstücks ist mit der Unterdruckquelle, also beispielsweise einer entsprechenden Saugpumpe, verbunden. Es versteht sich, dass anstelle der Saugpumpe auch ein Unterdruck-Speicherbehälter eingesetzt werden kann.According to the invention, it is particularly advantageous that a single vacuum pump can be used to provide ventilation and deaeration measures that are optimally adapted to the requirements of the heat treatment process. A T-shaped or Y-shaped connector is provided on the outlet connection of the dental furnace. An inlet of the connector is connected to the outlet connection of the dental furnace. The outlet of the connector is connected to the vacuum source, for example a corresponding suction pump. It goes without saying that a vacuum storage container can also be used instead of the suction pump.

Der andere Eingangsanschluss des Anschlussstücks ist mit der Umgebungsluft verbunden, und zwar bevorzugt in gesteuerter Weise, also mit einem Strömungswiderstand versehen. Der Strömungswiderstand kann als Ventil ausgebildet sein, dass in Abhängigkeit von den Erfordernissen des Wärmebehandlungsprozess geöffnet und geschlossen wird.The other inlet connection of the connector is connected to the ambient air, preferably in a controlled manner, i.e. provided with a flow resistance. The flow resistance can be designed as a valve that is opened and closed depending on the requirements of the heat treatment process.

Der Dentalofen weist ferner einen Einlassanschluss für die Brennkammer auf, der bevorzugt seinem Auslassanschluss gegenüberliegend angeordnet ist. Auch der Eingangsanschluss ist mit einer Leitung verbunden, die als zweite Luftleitung bezeichnet wird. Diese weist einen Strömungswiderstand wie beispielsweise einen Filter und/oder ein Ventil auf.The dental furnace also has an inlet connection for the combustion chamber, which is preferably arranged opposite its outlet connection. The inlet connection is also connected to a line, which is referred to as a second air line. This has a flow resistance such as a filter and/or a valve.

Die bevorzugte Vorgehensweise während des Wärmebehandlungsprozesses umfasst als ersten Schritt ein Evakuieren des Brennraums zur Vorbereitung des Wärmebehandlungsprozesses . Hierzu sind die Ventile in der ersten Luftleitung und der zweiten Luftleitung geschlossen, und die Saugpumpe arbeitet gegen den Unterdruck, bis ein vorgegebener Unterdruck oder das Endvakuum erreicht ist.The preferred procedure during the heat treatment process includes, as a first step, evacuating the combustion chamber in preparation for the heat treatment process. For this purpose, the valves in the first air line and the second air line are closed and the suction pump works against the negative pressure until a predetermined negative pressure or the final vacuum is reached.

Der Wärmebehandlungsprozesswird mit Aufheizen des Brennraums eingeleitet. Ab einem vorgegebenen Temperaturniveau wird nun das Ventil am Eingangsanschluss der Brennkammer geöffnet, während die Saugpumpe arbeitet. Das Öffnen kann kurzzeitig erfolgen, beispielsweise für eine Sekunde. Die in den Brennraum eingeführte Frischluft führt dazu, dass der Dentalrestauration Sauerstoff zugeleitet wird, ohne dass es zu einer massiven Abkühlung kommen würde.The heat treatment process is initiated by heating up the combustion chamber. Once a predetermined temperature level has been reached, the valve at the inlet connection of the combustion chamber is opened while the suction pump is running. The opening can be brief, for example for one second. The fresh air introduced into the combustion chamber means that oxygen is supplied to the dental restoration without causing it to cool down significantly.

Für den Abkühlprozess kann ebenfalls mit intermittierendem Öffnen des Eingangsanschluss-Ventils oder mit vollständigem Öffnen gearbeitet werden. Hierdurch kann die Saugpumpe den maximalen Volumenstrom durch den Brennraum ziehen.The cooling process can also be carried out by opening the inlet connection valve intermittently or by opening it completely. This allows the suction pump to draw the maximum volume flow through the combustion chamber.

Die austretende Luft kann gekühlt werden, beispielsweise über einen Wärmetauscher.The escaping air can be cooled, for example via a heat exchanger.

Je nach Bedarf besteht auch die Möglichkeit, den Brennraum über das Öffnen beider Ventile sehr rasch mit Frischluft zu fluten. Dies kann zur Prozessbeschleunigung und/oder zu Qualitätsverbesserungen des Dentalrestaurationsteils führen.Depending on requirements, it is also possible to flood the combustion chamber very quickly with fresh air by opening both valves. This can speed up the process and/or improve the quality of the dental restoration part.

Erfindungsgemäß ist es besonders günstig, dass die Abkühlzeit bei Bedarf stark verkürzt werden kann, indem durch das Frischluftspülen des Brennraums beim Abkühlprozess dem Brennraum Wärmeenergie entzogen werden kann. Bei gegenüberliegender Anordnung von Eingangsanschluss und Ausgangsanschluss wird die Wärme genau dort entfernt, wo es für die Abkühlung relevant ist, nämlich im Brennraum.According to the invention, it is particularly advantageous that the cooling time can be greatly reduced if necessary by removing heat energy from the combustion chamber during the cooling process by flushing the combustion chamber with fresh air. If the inlet connection and outlet connection are arranged opposite one another, the heat is removed exactly where it is relevant for cooling, namely in the combustion chamber.

Dies stellt einen erheblichen Fortschritt gegenüber einer freien Abkühlung dar, bei welcher hauptsächlich die Umgebung des Brennraums beeinflusst wird.This represents a significant improvement over free cooling, which mainly affects the environment of the combustion chamber.

Erfindungsgemäß kann ein Wärmetauscher vorgesehen sein, der Wärme von der Saugleitung zwischen dem Ausgang des Anschlussstücks und der Unterdruckquelle zur zweiten Luftleitung am Eingangsanschluss der Brennkammer überträgt.According to the invention, a heat exchanger can be provided which transfers heat from the suction line between the outlet of the connector and the vacuum source to the second air line at the inlet connection of the combustion chamber.

Eine derartige Wärmerückgewinnung ist insbesondere während des Aufheizens oder in einer in einem Zeitraum im Wärmebehandlungsprozess günstig, bei dem die Temperatur im Wesentlichen gehalten werden soll. Der Brennraum kann dann mit warmer Frischluft belüftet werden, ohne dass es zu einer schlagartigen Abkühlung und damit einhergehenden Risiken beim Wärmebehandlungsprozesskommt.Such heat recovery is particularly beneficial during heating or during a period in the heat treatment process when the temperature is essentially to be maintained. The combustion chamber can then be ventilated with warm fresh air without causing a sudden cooling and the associated risks in the heat treatment process.

Hierdurch wird zugleich auch die Saugleitung ab dem Wärmetauscher gekühlt, sodass der Einbau einer separaten Kühlfalle zum Schonen der Pumpe nicht erforderlich ist. Hierbei ist auch zu berücksichtigen, dass beim Wärmebehandlungsprozessggf. aggressive Dämpfe auftreten, gegen die die Saugleitung insbesondere bei heißen Temperaturen ansonsten geschützt werden müsste.This also cools the suction line from the heat exchanger, so that the installation of a separate cooling trap to protect the pump is not necessary. It should also be taken into account that aggressive vapors may arise during the heat treatment process, against which the suction line would otherwise have to be protected, especially at high temperatures.

Erfindungsgemäß ist es besonders günstig, wenn der Auslassanschluss des Ofens oben und der Einlassanschluss unten ist. Bei Bedarf lässt sich hierdurch die Kühlung des Brennraums optimieren.According to the invention, it is particularly advantageous if the outlet connection of the furnace is at the top and the inlet connection at the bottom. If necessary, this allows the cooling of the combustion chamber to be optimized.

In vorteilhafter Ausgestaltung ist es vorgesehen, das Anschlussstück aus gut wärmeleitenden Metall mit einer vergleichsweise großen Oberfläche auszubilden. Hierdurch ist es möglich, bereits an dieser Stelle Wärme abzuführen, nachdem das Anschlussstück von Umgebungsluft umgeben ist. Das Anschlussstück ist bevorzugt so ausgelegt, dass Gase mit Temperaturen bis zu 1200, 1400 oder gar 1600 Grad Celsius bei vorgegebenener Fördermenge von mehreren Litern / Minute das metallische Anschlussstück nicht schädigen.In an advantageous embodiment, the connecting piece is made of a metal with good heat conductivity and a relatively large surface area. This makes it It is possible to dissipate heat at this point, after the connector is surrounded by ambient air. The connector is preferably designed in such a way that gases with temperatures of up to 1200, 1400 or even 1600 degrees Celsius do not damage the metal connector at a given flow rate of several liters per minute.

Durch die Kühlung durch den Wärmetausch am Anschlussstück wird die austretende Luft deutlich gekühlt, sodass auslassseitig beispielsweise eine Maximaltemperatur von lediglich 500 Grad vorliegt.The cooling through the heat exchanger at the connector cools the escaping air significantly, so that on the outlet side, for example, the maximum temperature is only 500 degrees.

Wenn diese Temperatur für die verwendeten Materialien der Saugleitung zu hoch ist, besteht auch die Möglichkeit, das Ventil in der ersten Luftleitung beim Abpumpen heißer Luft zusätzlich zu öffnen, sodass im Anschlussstück heiße und kalte Luft gemischt wird und sich die Temperatur beispielsweise auf 200 Grad absenken lässt.If this temperature is too high for the materials used in the suction line, it is also possible to additionally open the valve in the first air line when pumping out hot air, so that hot and cold air are mixed in the connection piece and the temperature can be reduced to 200 degrees, for example.

Es versteht sich, dass die Ventile in der ersten Luftleitung und der zweiten Luftleitung als Ein-/Aus-Ventile ausgebildet sein können. Diese sind bevorzugt im stromlosen Zustand geschlossen. Es ist aber bei Bedarf auch möglich, das Ventil in der ersten Luftleitung und/oder das Ventil in der zweiten Luftleitung als regelbares Ventil auszubilden.It goes without saying that the valves in the first air line and the second air line can be designed as on/off valves. These are preferably closed when de-energized. However, if required, it is also possible to design the valve in the first air line and/or the valve in the second air line as an adjustable valve.

Wenn das Ventil in der ersten Luftleitung, das auch als Bypassventil bezeichnet werden kann, teilgeöffnet wird, entsteht eine Strömungsbegrenzung in der ersten Luftleitung. Hierdurch lässt sich der Volumenstrom durch den Brennraum bei Bedarf auf einen beliebigen Wert einstellen, sodass ein Teil der durch die Saugleitung abgeführten Luft durch die erste Luftleitung und ein anderer Teil durch die zweite Luftleitung und den Brennraum zugeführt wird.If the valve in the first air line, which can also be referred to as a bypass valve, is partially opened, a flow restriction is created in the first air line. This allows the volume flow through the combustion chamber to be set to any value as required, so that part of the air discharged through the suction line is fed through the first air line and another part is fed through the second air line and the combustion chamber.

Hierdurch lässt sich auch allenfalls durch die Förderung entstehende Unterdruck in der Brennkammer trotz Verwendung einer Einfach-Saugpumpe reduzieren, wenn dies erwünscht ist.This also makes it possible to reduce any negative pressure in the combustion chamber caused by the pumping process, despite the use of a single suction pump, if this is desired.

In weiterer vorteilhafter Ausgestaltung ist vorgesehen, die erste Luftleitung so zu führen, dass die dort zugeführte Frischluft andere Komponenten kühlt. Hierzu gehört zum Beispiel die Leistungselektronik des Dentalofens, die typischerweise im Ofenunterteil untergebracht ist. Es ist auch möglich, die Luft durch die erste Luftleitung außerhalb der Wärmedämmung der Ofenhaube durchströmen zu lassen, um die meist metallische Gehäusewand der Ofenhaube vorsorglich weiter zu kühlen.In a further advantageous embodiment, the first air line is designed in such a way that the fresh air supplied there cools other components. This includes, for example, the power electronics of the dental furnace, which is typically housed in the lower part of the furnace. It is also possible to let the air flow through the first air line outside the thermal insulation of the furnace hood in order to further cool the usually metallic housing wall of the furnace hood as a precaution.

Wenn die Saugpumpe unmittelbar benachbart dem Ofen angeordnet ist und dementsprechend eine kurze Saugleitung vorliegt, kann es vorteilhaft sein, eine Kühlfalle in die Saugleitung kurz vor der Saugpumpe einzusetzen.If the suction pump is located immediately adjacent to the furnace and the suction line is therefore short, it may be advantageous to insert a cold trap into the suction line shortly before the suction pump.

Bevorzugt ist das Anschlussstück unmittelbar an dem Dentalofen angebracht, also auf beispielsweise auf die Ofenhaube montiert. Im Einzelfall kann es sinnvoll sein das Anschlussstück etwas entfernt von dem Dentalofen zu montieren, wobei es sich versteht, dass die dann kurze Hochtemperaturleitung zwischen Anschlussstück und Dentalofen dann besonders temperaturfest sein muss.Preferably, the connector is attached directly to the dental furnace, for example, mounted on the furnace hood. In individual cases, it may be useful to mount the connector a little away from the dental furnace, although it goes without saying that the short high-temperature line between the connector and the dental furnace must then be particularly temperature-resistant.

Fernen ist es auch möglich, mehr als einen Anschluss für die Absaugung zu verwenden und beispielsweise ein Anschlussstück rechts oben an der Ofenhaube und ein Anschlussstück links oben an der Ofenhaube anzuordnen, oder einander gegenüberliegend rechts oben und links unten oder andersherum. Der Eingangsanschluss ist dann jedoch je von den Anschlussstücken deutlich benachbart; der Eingangsanschluss und die Anschlussstücke können dann insofern etwa im Dreieck angeordnet sein, sodass die durch den Eingangsanschluss zutretende Frischluft zu den Anschlussstücken hin jeweils den Brennraum durchströmt.It is also possible to use more than one connection for the extraction and, for example, to arrange a connection piece at the top right of the oven hood and a connection piece at the top left of the oven hood, or opposite each other at the top right and bottom left, or the other way around. However, the inlet connection is then clearly adjacent to each of the connection pieces; the inlet connection and the connection pieces can then be arranged in a triangle, so that the fresh air entering through the inlet connection flows through the combustion chamber towards the connection pieces.

Die Saugpumpe lässt sich bei Bedarf auch getaktet betreiben, sodass in der Summe ein reduzierter Volumenstrom bereitgestellt wird. Durch eine vergleichsweise lange Saugleitung besteht ein Unterdruckpuffer, der die Schaltwirkungen der Taktung reduziert.If required, the suction pump can also be operated in a cyclical manner, so that a reduced volume flow is provided overall. A comparatively long suction line creates a vacuum buffer that reduces the switching effects of the cyclical operation.

Da typischerweise preisgünstige Saugpumpen recht laut sind, kommt es auch in Betracht, die Saugpumpe außerhalb des Raums, in dem der Dentalofen angeordnet ist, zu betreiben. Die Saugleitung kann dann 5, 10 oder sogar 20 Meter lang sein, sodass aufgrund einer derart langen Saugleitung auch eine Kühlfalle entbehrlich ist.Since inexpensive suction pumps are typically quite loud, it is also possible to operate the suction pump outside the room in which the dental furnace is located. The suction line can then be 5, 10 or even 20 meters long, so that a cooling trap is also unnecessary due to such a long suction line.

Erfindungsgemäß ist es jedenfalls möglich, je nach Vorgaben des Wärmebehandlungsprozess den maximalen Unterdruck oder einen geringeren Unterdruck während unterschiedlicher Temperaturniveaus bereitzustellen. Durch den Wärmetauscher lässt sich der Wärmeentzug hierbei minimieren. Alternativ lässt sich auch ein rasches Abkühlen bewerkstelligen, wobei es auch möglich ist, ein Bypass über den Wärmetauscher eingangsseitig zu legen, sodass seine Wirkung bei Bedarf abschaltbar ist.According to the invention, it is possible to provide the maximum negative pressure or a lower negative pressure at different temperature levels, depending on the specifications of the heat treatment process. The heat extraction can be minimized by the heat exchanger. Alternatively, rapid cooling can also be achieved, whereby it is also possible to place a bypass over the heat exchanger on the inlet side so that its effect can be switched off if necessary.

Es versteht sich, dass die Strömungsquerschnitte der Leitungen in strömungstechnischer Hinsicht an die Erfordernisse angepasst werden können. Wenn beispielsweise mit einer Saugleitung und einer ersten und einer zweiten Luftleitung gearbeitet wird, ist bevorzugt der Strömungsquerschnitt der Saugleitung doppelt so groß wie der der Luftleitungen. Dies gilt sinngemäß natürlich auch für das Anschlussstück, das in der einfachsten Version kurzerhand zwei Bohrungen als Eingänge und eine Bohrung als Ausgang aufweist, die einander treffen. Das Anschlussstück kann insofern Y-förmig, T-förmig oder sternförmig ausgebildet sein. Es kann bei Bedarf auch mit einem Berührungsschutz versehen sein, beispielsweise einer Abdeckung, die mehrere Zentimeter Luft belässt.It goes without saying that the flow cross-sections of the lines can be adapted to the requirements in terms of flow technology. For example, if a If a suction line and a first and a second air line are used, the flow cross-section of the suction line is preferably twice as large as that of the air lines. This also applies to the connector, which in the simplest version has two holes as inlets and one hole as outlet that meet each other. The connector can therefore be Y-shaped, T-shaped or star-shaped. If necessary, it can also be provided with contact protection, for example a cover that leaves several centimeters of air.

Das Anschlussstück kann auch mit einem vergleichsweise langen Anschlussstutzen für die erste Luftleitung versehen sein. Dieser kann auch Kühlrippen ausbilden, sodass das insgesamt metallische Anschlussstück durch die Zuleitung der kühlen Luft über die erste Luftleitung gekühlt wird.The connector can also be provided with a relatively long connection piece for the first air line. This can also form cooling fins so that the entire metallic connector is cooled by the supply of cool air via the first air line.

Der Wärmehandlungsprozess kann ein Sinterprozess oder ein Brennprozess sein.The heat treatment process can be a sintering process or a firing process.

Weitere Vorteile, Einzelheiten und Merkmale ergeben sich aus der nachfolgenden Beschreibung eines Ausführungsbeispiels der Erfindung anhand der Zeichnung.Further advantages, details and features will become apparent from the following description of an embodiment of the invention with reference to the drawing.

Es zeigt:
Die einzige Figur der Zeichnung eine schematische Anordnung von verschiedenen Leitungen und Schaltelementen eines erfindungsgemäßen Dentalofen.It shows:
The only figure in the drawing shows a schematic arrangement of various lines and switching elements of a dental furnace according to the invention.

Der in der Figur schematisch dargestellte Dentalofen 10 weist eine Brennkammer oder einen Brennraum 12 auf, der in einem Ofenkopf 14 ausgebildet ist. Der Ofenkopf 14 schließt an einer Trennebene 16 gegenüber einem Ofenunterteil 18.The dental furnace 10 shown schematically in the figure has a combustion chamber or a combustion space 12 which is formed in a furnace head 14. The furnace head 14 closes at a parting plane 16 opposite a furnace base 18.

in an sich bekannter Weise weist der Ofenkopf 14 Heizelemente auf, die sich ringförmig um den im Wesentlichen zyllindrischen Brennraum 12 erstrecken. Sowohl der Ofenkopf 14 als auch das Ofenunterteil 18 sind mit Wärmedämmmaterial 20 versehen, das beispielsweise als Schamott ausgebildet sein kann und offenporig ist, sodass es durchströmbar ist.In a manner known per se, the furnace head 14 has heating elements which extend in a ring shape around the essentially cylindrical combustion chamber 12. Both the furnace head 14 and the furnace base 18 are provided with thermal insulation material 20, which can be designed as fireclay, for example, and is open-pored so that air can flow through it.

Erfindungsgemäß ist der Dentalofen 10 mit einem Einlassanschluss 22 für die Zufuhr von Umgebungsluft, die auch als Frischluft bezeichnet werden kann, sowie mit einem Auslassanschluss 24 versehen, an dem ein Anschlussstück 26 angebracht ist.According to the invention, the dental furnace 10 is provided with an inlet connection 22 for the supply of ambient air, which can also be referred to as fresh air, and with an outlet connection 24 to which a connection piece 26 is attached.

Das Anschlussstück 26 ist direkt an der Gehäusewand 30 des Ofenkopfes 14 angeflanscht. Es weist einen Eingang 32 auf, der in Strömungsverbindung mit dem offenporigen Wärmedämmmaterial 20 steht. Fernen weist es einen zweiten Eingang 34 auf, der über eine erste Luftleitung 36 mit Umgebungsluft in Verbindung steht.The connecting piece 26 is flanged directly to the housing wall 30 of the furnace head 14. It has an inlet 32 which is in flow connection with the open-pore thermal insulation material 20. It also has a second inlet 34 which is in connection with ambient air via a first air line 36.

Ferner weist das Anschlussstück 26 einen Ausgang 40 auf, der mit einer Saugleitung 42 in Strömungsverbindung steht.Furthermore, the connecting piece 26 has an outlet 40 which is in flow connection with a suction line 42.

In dem dargestellten Ausführungsbeispiel erstrecken sich sowohl die erste Luftleitung 36 als auch die Saugleitüng 42 zunächst im Bereich des Ofenkopfes 14 und von hier ausgehend nach unten, also in den Bereich des Ofenunterteils 18, und ggf. seitlich weg von diesem.In the illustrated embodiment, both the first air line 36 and the suction line 42 extend initially in the region of the furnace head 14 and from there downwards, i.e. into the region of the furnace base 18, and possibly laterally away from it.

Die Saugleitung 42 erstreckt sich zu einer Unterdruckquelle 44, die bevorzugt als Saugpumpe 44 ausgebildet ist und deren Abluft bevorzugt außerhalb des Raums geführt wird, in dem der Dentalofen steht.The suction line 42 extends to a vacuum source 44, which is preferably designed as a suction pump 44 and whose exhaust air is preferably guided outside the room in which the dental furnace is located.

Der Eingangsanschluss 22 ist mit einer zweiten Luftleitung 46 in Verbindung.The inlet connection 22 is connected to a second air line 46.

Die erste Luftleitung 36 ist mit einem Bypassventil 48 versehen, über welches sie mit einem Filter und/oder Schalldämpfer 50 mit der Umgebungsluft in Verbindung steht.The first air line 36 is provided with a bypass valve 48, via which it is connected to the ambient air via a filter and/or silencer 50.

In ähnlicher Weise ist die zweite Luftleitung 46 mit einem zweiten Ventil 54 versehen, über welches sie mit einem zweiten Filter und/oder Schalldämpfer 56 mit der Umgebungsluft in Verbindung steht.Similarly, the second air line 46 is provided with a second valve 54, via which it is connected to the ambient air via a second filter and/or silencer 56.

In dem dargestellten Ausführungsbeispiel ist ein Unterdrucksensor 60 vorgesehen, der über eine Stichleitung 62 mit dem Inneren des Dentalofens 10 in Verbindung steht. Hierdurch lässt sich der bestehende Unterdruck im Brennraum 12 erfassen und für die Steuerung der beiden Ventile 48 und 54 und der Saugpumpe 44 einsetzen.In the embodiment shown, a vacuum sensor 60 is provided, which is connected to the interior of the dental furnace 10 via a branch line 62. This allows the existing vacuum in the combustion chamber 12 to be detected and used to control the two valves 48 and 54 and the suction pump 44.

Für die Durchführung eines Wärmebehandlungsprozesswird nun in dem hier dargestellten Ausführungsbeispiel zunächst das Bypassventil 48 und das zweite Ventil 54 geschlossen und die Saugpumpe 44 eingeschaltet.To carry out a heat treatment process, in the embodiment shown here, the bypass valve 48 and the second valve 54 are first closed and the suction pump 44 is switched on.

Alternativ kann auch zunächst für eine kurze Zeit das zweite Ventil 54 in der geöffneten Stellung gehalten werden, um etwaige Restgase des letzten Wärmebehandlungsprozesses sicher zu entfernen.Alternatively, the second valve 54 can initially be held in the open position for a short time in order to safely remove any residual gases from the last heat treatment process.

Hieran anschließend wird der Wärmebehandlungsprozessbegonnen, in dem die nicht dargestellte Heizung für den Brennraum 12 eingeschaltet wird. Dies erfolgt unter Unterdruck, und der Unterdruck wird aufrechterhalten, nachdem die Saugpumpe 44 während dieser Zeit betrieben wird, sodass auch etwaige geringe Undichtigkeiten den Unterdruck nicht vermindern.The heat treatment process is then started by switching on the heating (not shown) for the combustion chamber 12. This is done under negative pressure, and the negative pressure is maintained after the suction pump 44 is operated during this time, so that even small leaks do not reduce the negative pressure.

Wenn die Temperatur für den weiteren Abschnitt des Wärmebehandlungsprozessesabgesenkt werden soll, wird die Saugpumpe 44 erneut eingeschaltet und das Ventil 54 geöffnet. Hierdurch wird der Brennraum 12 mit Frischluft gespült und es ist bei Bedarf möglich, eine rasche Abkühlung bereit zu stellen. Die Saugpumpe 44 kann hierbei auch getaktet eingeschaltet werden, wenn die Abkühlung nicht so schnell erfolgen soll.If the temperature is to be lowered for the next section of the heat treatment process, the suction pump 44 is switched on again and the valve 54 is opened. This flushes the combustion chamber 12 with fresh air and, if necessary, it is possible to provide rapid cooling. The suction pump 44 can also be switched on intermittently if the cooling is not to take place so quickly.

Dieses Verfahren ist jedenfalls günstiger als das Öffnen des Brennraums an der Trennlinie 16, nachdem ansonsten schlagartig stets Kühlluft zugeführt wird.In any case, this method is more advantageous than opening the combustion chamber at the dividing line 16, since otherwise cooling air is always supplied suddenly.

Bei einem modifizierten Verfahren wird auch das Bypassventil 44 während des Betriebs der Saugpumpe 44 mindestens teilweise geöffnet. Hierdurch lässt sich die Höhe des Unterdrucks, der von dem Unterdrucksensor 60 gemessen wird, steuern.In a modified method, the bypass valve 44 is also at least partially opened during operation of the suction pump 44. This makes it possible to control the level of the negative pressure measured by the negative pressure sensor 60.

In einer weiteren modifizierten Ausgestaltung ist es vorgesehen, die Saugleitung 44 und die zweite Luftleitung 46 nah aneinander heranzuführen und zwischen diesen einen Wärmetauscher bereitzustellen. Hierdurch lässt sich die aus dem Ausgang 44 austretende heiße Ofenluft thermisch wiedergewinnen und der Luftleitung 46 zuführen, was insbesondere für das Aufheizen günstig ist.In a further modified embodiment, the suction line 44 and the second air line 46 are brought close to one another and a heat exchanger is provided between them. This allows the hot oven air exiting from the outlet 44 to be thermally recovered and fed to the air line 46, which is particularly advantageous for heating.

Der Wärmetauscher kann je auch bei Bedarf mit einer zusätzlichen Bypassleitung eingangsseitig und/oder ausgangsseitig versehen sein, die wiederum ein Ventil aufweisen kann. Durch das Ventil wird die betreffende Seite des Wärmetauschers gleichsam kurzgeschlossen, sodass die Wärmetauscherwirkung umgangen wird, wie es insbesondere für das Abkühlen und die Zufuhr kalter Frischluft günstig ist.If required, the heat exchanger can also be provided with an additional bypass line on the inlet and/or outlet side, which in turn can have a valve. The valve short-circuits the relevant side of the heat exchanger, so that the heat exchanger effect is bypassed, which is particularly beneficial for cooling and the supply of cold fresh air.

Der erfindungsgemäße Dentalofen kann auch als ein Entbinderungsofen ausgebildet sein. Die dort erzeugte Abluft lässt sich erfindungsgemäß besonders gut mit der erfindungsgemäßen Saugpumpe 44 und den zugehörigen Ventilen abführen.The dental furnace according to the invention can also be designed as a debinding furnace. The exhaust air generated there can be removed particularly well according to the invention using the suction pump 44 according to the invention and the associated valves.

Claims (13)

  1. A dental furnace having a closed or closable firing chamber (12), which is surrounded by a thermal insulation (20) and which has at least one inlet port (22) and at least one outlet port (24), through both of which a gas, in particular air, is passable through the firing chamber (12) and/or dischargeable from the firing chamber (12), wherein a vacuum source (44) is provided, which is in direct or indirect communication with the outlet port (24) and by which the outlet port (24) may be depressurized, characterized in that at the outlet port (24) an in particular T-shaped or Y-shaped connector (26) is attached, in that the connector (26) comprises two inlets (32, 24) and one outlet (40), wherein the outlet (40) is in communication with the vacuum source (44) and a first inlet is in communication with the firing chamber (12), particularly is flange-mounted to the outlet port (24) thereof, and a second inlet (34) is in communication with ambient air, namely in a controlled manner, in particular with a flow resistance.
  2. The dental furnace according to claim 1, characterized in that the second inlet (34) of the connector (26) is connected to a first air line (36) via one or more members having a flow resistance, especially a valve (48).
  3. The dental furnace according to one of the preceding claims, characterized in that the inlet port (22) and the outlet port (24), in terms of the firing chamber (12) of the dental furnace (10), are arranged opposite each other such that at least part of the firing chamber (12) extends therebetween.
  4. The dental furnace according to one of the preceding claims, characterized in that the inlet port (22) is connected to a second air line (46) which comprises a valve (54) and/or a filter (56).
  5. The dental furnace according to one of the preceding claims, characterized in that a suction line (42) extends between the connector (26) and the vacuum source (44), enabling heat exchange between the ambient air and the suction air passing through the suction line (42) due to the material used for the suction line (42).
  6. The dental furnace according to claim 5, characterized in that the suction line (42) comprises a heat exchanger which is also connected to the air line (36) of the inlet (34) of the dental furnace (10).
  7. The dental furnace according to claim 6, characterized in that the heat exchanger is provided with a bypass line which is provided with a switching valve between the bypass and heat exchanger.
  8. The dental furnace according to one of the preceding claims, characterized in that the connector (26) consists of thermally conductive material, such as metal, and that the second inlet (34) is provided with a connecting piece of several centimeters in length, in particular 10 cm in length.
  9. The dental furnace according to one of the preceding claims, characterized in that the connecting piece or the connector comprises an enlarged surface, in particular cooling ribs.
  10. The dental furnace according to one of the preceding claims, characterized in that the fresh air line (36) supplying fresh air to the second inlet (34) of the connector (26), is connected to external heat sources of the dental furnace (10), such as the power electronics, and cools the same.
  11. The dental furnace according to one of the preceding claims, characterized in that at least two inlet ports (22) for supplying fresh air to the firing chamber (12) are provided, which are arranged spaced apart from each other and are located opposite the outlet port (24).
  12. The dental furnace according to one of the preceding claims, characterized in that at least two outlet ports (24) are provided, which are arranged opposite the inlet port(s) (22), wherein both outlet ports (24) are joined at the connector (26).
  13. A method for operating a dental furnace, in particular a dental furnace according to one of the preceding claims, using a heat treatment process for the dental restoration(s), characterized in that an outlet port (24) is attached to the firing chamber of the dental furnace (10), through which a gas is dischargeable from the firing chamber (12), in particular by way of negative pressure, in that the firing chamber (12) of the dental furnace (10) is evacuated via the outlet port (24) prior to starting the heat treatment process or when starting the heat treatment process, in particular by a maximum volume flow, and in that at least part of the heat treatment process is performed in the evacuated state and the firing chamber (12) is increasingly supplied with ambient air at a predetermined temperature during the cooling, or at another point in time of the heat treatment process ambient air is continuously sucked through the firing chamber (12) by turning on the vacuum source (44), in particular via an inlet port (22).
EP17191620.8A 2017-09-18 2017-09-18 Dental oven and method for operating same Active EP3457064B1 (en)

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EP17191620.8A EP3457064B1 (en) 2017-09-18 2017-09-18 Dental oven and method for operating same
CN201811053346.2A CN109512534A (en) 2017-09-18 2018-09-11 Dental furnace and method for running dental furnace
US16/128,672 US10955192B2 (en) 2017-09-18 2018-09-12 Dental furnace as well as method for operating a dental furnace
JP2018173578A JP6814183B2 (en) 2017-09-18 2018-09-18 How to operate a dental kiln and a dental kiln

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US4324545A (en) * 1980-09-22 1982-04-13 Gladd Industries, Inc. Recirculating heater for processing oven
JPS6012271A (en) * 1983-07-04 1985-01-22 M C L:Kk Casting device
DE4303458C1 (en) * 1993-02-08 1994-01-27 Hinterberger Dr Karl Firing furnace for dental ceramic coatings - has internal screens and gas lines for protective atmos. prodn.
JPH11337269A (en) * 1998-05-29 1999-12-10 Nok Corp Baking equipment
JP2001116482A (en) * 1999-10-19 2001-04-27 Babcock Hitachi Kk Fin material heat transfer tube, its manufacturing method, finned heat-transfer tube and its manufacturing method
JP2003214603A (en) * 2002-01-22 2003-07-30 Ngk Insulators Ltd Reducing combustion burner apparatus and non-oxidation kiln
DE10208801C1 (en) 2002-03-01 2003-06-12 Horst-Juergen Heidenegger Vacuum furnace firing pressed ceramic false teeth, includes upper piston drive unit connected to vacuum pump and main chamber
JP2011073907A (en) 2009-09-29 2011-04-14 World Lab:Kk Sintered body of zirconia and method for manufacturing the same
CN102032784A (en) * 2010-12-17 2011-04-27 湖南航天工业总公司 Multifunctional microwave sintering test furnace
ES2438721T3 (en) * 2011-07-25 2014-01-20 Ivoclar Vivadent Ag Dental oven
CN103764424B (en) * 2011-08-31 2016-06-08 丰田自动车株式会社 Vehicle and be equipped on the cooling construction of supply unit of vehicle
CN106662400B (en) * 2014-07-07 2019-09-13 株式会社Ihi Annealing device

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JP6814183B2 (en) 2021-01-13
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US20190086150A1 (en) 2019-03-21
US10955192B2 (en) 2021-03-23
JP2019051318A (en) 2019-04-04

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